Phase-change medium usable in phase-difference tracking
US6426936B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 25, 1999 |
| Grant date | Jul 30, 2002 |
| Priority date | — |
| Expiry date | Jan 25, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/24316
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A product for recording information by use of laser light includes a recording layer being able to change between an amorphous state and a crystalline state so as to record information, the recording layer having a thickness falling within a first range defined relative to a wavelength of the laser light, a protection layer having a thickness falling within a second range defined relative to the wavelength of the laser light, a heat releasing layer having a thickness falling within a third range defined relative to the wavelength of the laser light, and a transparent substrate supporting the layers. The first, second, and third ranges are selected such that a phase of the laser light reflected by the amorphous state and a phase of the laser light reflected by the crystalline state have a phase difference larger than a predetermined phase amount.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.